Isn't economy a from of vodoo?

A while ago I learned that the economy is assigns. This is not true. I have the feeling that economy is at times of voodoo. How do I come up with this idea? From my understanding there are two ways to do economy. The first one is talking and talking and the second one is building a mathematical model and play with it. Okay, talking and talking is sometimes very entertaining. But when you have heard two or three economists you get the feeling that their arguments could be a right but could be also wrong. As soon as you start thinking about what they are saying you normally find always a mistake in the logic. Therefore, I call these people just entertainer. The other group isn't there. What these group is doing is nothing else than solving some mathematical equations. But as soon as you look at the building blocks of the model you find assumptions which aren't true. The market isn't efficient; the human beings on national. Therefore I can't see any scientific foundation.